I think the productivity tips are good ones. But something must be different about his university than mine. Finishing two difficult degrees (math and CS) in 3 semesters is simply not possible in most if not all US Universities. Perhaps this is somewhere else? He does call them units instead of hours. He even says that the last semester he also worked 40 hours a week and that he ran a club and socialized with friends.

First of all, most universities don't even offer all the courses you need to graduate every semester and when they do, they are often overlapping. You certainly couldn't fit them all in with a full time job as well. Did none of these classes have homework or turn in assignments? He also says he slept 7-8 hrs a day and at least one semester had classes from 9am-10pm. Sorry, but most of those classes must have been a joke. You can't absorb that much information in a day and the 3 remaining waking hours is not enough to study and review the material, prep for tests, and take care of daily life stuff.

The number of credits required for graduation must also be low. Especially for two degrees even considering that they would have a lot of overlap. I tested out of every credit possible at my university and was able to complete 2 degrees in 8 semesters. And I had a full class schedule, around 30 hours a semester and I had to plan very carefully, sometimes 1 or 2 semesters in advance just to make sure my necessary courses would be available and not overlapping.